Speeding up image bluring with MMX & SSE

This is program for my Polish article Rozmycie obrazów (Blurring images); try Google translate if you wish, it gives quite good translation.

Short introduction

Blurring in this case means calculating following kernel:

+---+---+---+
| 1 | 1 | 1 |
+---+---+---+
| 1 | 1 | 1 |
+---+---+---+
| 1 | 1 | 1 |
+---+---+---+

where bias is 0 and divisor is 9.

Following observation have made possible significant speedup:

• each pixel could be fetched excatly once;
• some calculation can be shared across calculations for adjacent blocks.

Sample program

The sample program contains several implementations:

• x86 --- a scalar reference implementation;
• MMX --- an MMX variant of the scalar algorithm;
• MMX2 --- an MMX variant with minimized memory fetches;
• SSE2 --- an SSE2 variant of the MMX implementation.

Results from Core i5

CPU: Core i5 M 540 @ 2.53GHz

Note: a 32-bit code

proc	time [s]	speedup
x86	0:08.27	1.00	█████
mmx	0:01.82	4.52	██████████████████████
mmx2	0:02.35	3.52	█████████████████
sse2	0:01.04	7.95	████████████████████████████████████████